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<a name="1" href="#1">1</a>   <em class="jxr_comment">/*</em>
<a name="2" href="#2">2</a>   <em class="jxr_comment"> *  Copyright 2001-2005 Stephen Colebourne</em>
<a name="3" href="#3">3</a>   <em class="jxr_comment"> *</em>
<a name="4" href="#4">4</a>   <em class="jxr_comment"> *  Licensed under the Apache License, Version 2.0 (the "License");</em>
<a name="5" href="#5">5</a>   <em class="jxr_comment"> *  you may not use this file except in compliance with the License.</em>
<a name="6" href="#6">6</a>   <em class="jxr_comment"> *  You may obtain a copy of the License at</em>
<a name="7" href="#7">7</a>   <em class="jxr_comment"> *</em>
<a name="8" href="#8">8</a>   <em class="jxr_comment"> *      <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
<a name="9" href="#9">9</a>   <em class="jxr_comment"> *</em>
<a name="10" href="#10">10</a>  <em class="jxr_comment"> *  Unless required by applicable law or agreed to in writing, software</em>
<a name="11" href="#11">11</a>  <em class="jxr_comment"> *  distributed under the License is distributed on an "AS IS" BASIS,</em>
<a name="12" href="#12">12</a>  <em class="jxr_comment"> *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</em>
<a name="13" href="#13">13</a>  <em class="jxr_comment"> *  See the License for the specific language governing permissions and</em>
<a name="14" href="#14">14</a>  <em class="jxr_comment"> *  limitations under the License.</em>
<a name="15" href="#15">15</a>  <em class="jxr_comment"> */</em>
<a name="16" href="#16">16</a>  <strong class="jxr_keyword">package</strong> org.goda.time.tz;
<a name="17" href="#17">17</a>  
<a name="18" href="#18">18</a>  <strong class="jxr_keyword">import</strong> org.goda.time.DateTimeZone;
<a name="19" href="#19">19</a>  
<a name="20" href="#20">20</a>  <em class="jxr_javadoccomment">/**</em>
<a name="21" href="#21">21</a>  <em class="jxr_javadoccomment"> * Improves the performance of requesting time zone offsets and name keys by</em>
<a name="22" href="#22">22</a>  <em class="jxr_javadoccomment"> * caching the results. Time zones that have simple rules or are fixed should</em>
<a name="23" href="#23">23</a>  <em class="jxr_javadoccomment"> * not be cached, as it is unlikely to improve performance.</em>
<a name="24" href="#24">24</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a name="25" href="#25">25</a>  <em class="jxr_javadoccomment"> * CachedDateTimeZone is thread-safe and immutable.</em>
<a name="26" href="#26">26</a>  <em class="jxr_javadoccomment"> * </em>
<a name="27" href="#27">27</a>  <em class="jxr_javadoccomment"> * @author Brian S O'Neill</em>
<a name="28" href="#28">28</a>  <em class="jxr_javadoccomment"> * @since 1.0</em>
<a name="29" href="#29">29</a>  <em class="jxr_javadoccomment"> */</em>
<a name="30" href="#30">30</a>  <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">class</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">CachedDateTimeZone</a> <strong class="jxr_keyword">extends</strong> <a href="../../../../org/goda/time/DateTimeZone.html">DateTimeZone</a> {
<a name="31" href="#31">31</a>  
<a name="32" href="#32">32</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">long</strong> serialVersionUID = 5472298452022250685L;
<a name="33" href="#33">33</a>  
<a name="34" href="#34">34</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">int</strong> cInfoCacheMask;
<a name="35" href="#35">35</a>  
<a name="36" href="#36">36</a>      <strong class="jxr_keyword">static</strong> {
<a name="37" href="#37">37</a>  <em class="jxr_comment">//        Integer i = null;</em>
<a name="38" href="#38">38</a>  <em class="jxr_comment">//        try {</em>
<a name="39" href="#39">39</a>  <em class="jxr_comment">//            i = Integer.getInteger("org.joda.time.tz.CachedDateTimeZone.size");</em>
<a name="40" href="#40">40</a>  <em class="jxr_comment">//        } catch (SecurityException e) {</em>
<a name="41" href="#41">41</a>  <em class="jxr_comment">//            i = null;</em>
<a name="42" href="#42">42</a>  <em class="jxr_comment">//        }</em>
<a name="43" href="#43">43</a>  
<a name="44" href="#44">44</a>          <strong class="jxr_keyword">int</strong> cacheSize;
<a name="45" href="#45">45</a>  <em class="jxr_comment">//        if (i == null) {</em>
<a name="46" href="#46">46</a>              <em class="jxr_comment">// With a cache size of 512, dates that lie within any 69.7 year</em>
<a name="47" href="#47">47</a>              <em class="jxr_comment">// period have no cache collisions.</em>
<a name="48" href="#48">48</a>              cacheSize = 512; <em class="jxr_comment">// (1 &lt;&lt; 9)</em>
<a name="49" href="#49">49</a>  <em class="jxr_comment">//        } else {</em>
<a name="50" href="#50">50</a>  <em class="jxr_comment">//            cacheSize = i.intValue();</em>
<a name="51" href="#51">51</a>  <em class="jxr_comment">//            // Ensure cache size is even power of 2.</em>
<a name="52" href="#52">52</a>  <em class="jxr_comment">//            cacheSize--;</em>
<a name="53" href="#53">53</a>  <em class="jxr_comment">//            int shift = 0;</em>
<a name="54" href="#54">54</a>  <em class="jxr_comment">//            while (cacheSize &gt; 0) {</em>
<a name="55" href="#55">55</a>  <em class="jxr_comment">//                shift++;</em>
<a name="56" href="#56">56</a>  <em class="jxr_comment">//                cacheSize &gt;&gt;= 1;</em>
<a name="57" href="#57">57</a>  <em class="jxr_comment">//            }</em>
<a name="58" href="#58">58</a>  <em class="jxr_comment">//            cacheSize = 1 &lt;&lt; shift;</em>
<a name="59" href="#59">59</a>  <em class="jxr_comment">//        }</em>
<a name="60" href="#60">60</a>  
<a name="61" href="#61">61</a>          cInfoCacheMask = cacheSize - 1;
<a name="62" href="#62">62</a>      }
<a name="63" href="#63">63</a>  
<a name="64" href="#64">64</a>      <em class="jxr_javadoccomment">/**</em>
<a name="65" href="#65">65</a>  <em class="jxr_javadoccomment">     * Returns a new CachedDateTimeZone unless given zone is already cached.</em>
<a name="66" href="#66">66</a>  <em class="jxr_javadoccomment">     */</em>
<a name="67" href="#67">67</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">CachedDateTimeZone</a> forZone(<a href="../../../../org/goda/time/DateTimeZone.html">DateTimeZone</a> zone) {
<a name="68" href="#68">68</a>          <strong class="jxr_keyword">if</strong> (zone instanceof CachedDateTimeZone) {
<a name="69" href="#69">69</a>              <strong class="jxr_keyword">return</strong> (CachedDateTimeZone)zone;
<a name="70" href="#70">70</a>          }
<a name="71" href="#71">71</a>          <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">new</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">CachedDateTimeZone</a>(zone);
<a name="72" href="#72">72</a>      }
<a name="73" href="#73">73</a>  
<a name="74" href="#74">74</a>      <em class="jxr_comment">/*</em>
<a name="75" href="#75">75</a>  <em class="jxr_comment">     * Caching is performed by breaking timeline down into periods of 2^32</em>
<a name="76" href="#76">76</a>  <em class="jxr_comment">     * milliseconds, or about 49.7 days. A year has about 7.3 periods, usually</em>
<a name="77" href="#77">77</a>  <em class="jxr_comment">     * with only 2 time zone offset periods. Most of the 49.7 day periods will</em>
<a name="78" href="#78">78</a>  <em class="jxr_comment">     * have no transition, about one quarter have one transition, and very rare</em>
<a name="79" href="#79">79</a>  <em class="jxr_comment">     * cases have multiple transitions.</em>
<a name="80" href="#80">80</a>  <em class="jxr_comment">     */</em>
<a name="81" href="#81">81</a>  
<a name="82" href="#82">82</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <a href="../../../../org/goda/time/DateTimeZone.html">DateTimeZone</a> iZone;
<a name="83" href="#83">83</a>  
<a name="84" href="#84">84</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">transient</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a>[] iInfoCache;
<a name="85" href="#85">85</a>  
<a name="86" href="#86">86</a>      <strong class="jxr_keyword">private</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">CachedDateTimeZone</a>(<a href="../../../../org/goda/time/DateTimeZone.html">DateTimeZone</a> zone) {
<a name="87" href="#87">87</a>          <strong class="jxr_keyword">super</strong>(zone.getID());
<a name="88" href="#88">88</a>          iZone = zone;
<a name="89" href="#89">89</a>          iInfoCache = <strong class="jxr_keyword">new</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a>[cInfoCacheMask + 1];
<a name="90" href="#90">90</a>      }
<a name="91" href="#91">91</a>  
<a name="92" href="#92">92</a>      <em class="jxr_javadoccomment">/**</em>
<a name="93" href="#93">93</a>  <em class="jxr_javadoccomment">     * Returns the DateTimeZone being wrapped.</em>
<a name="94" href="#94">94</a>  <em class="jxr_javadoccomment">     */</em>
<a name="95" href="#95">95</a>      <strong class="jxr_keyword">public</strong> <a href="../../../../org/goda/time/DateTimeZone.html">DateTimeZone</a> getUncachedZone() {
<a name="96" href="#96">96</a>          <strong class="jxr_keyword">return</strong> iZone;
<a name="97" href="#97">97</a>      }
<a name="98" href="#98">98</a>  
<a name="99" href="#99">99</a>      <strong class="jxr_keyword">public</strong> String getNameKey(<strong class="jxr_keyword">long</strong> instant) {
<a name="100" href="#100">100</a>         <strong class="jxr_keyword">return</strong> getInfo(instant).getNameKey(instant);
<a name="101" href="#101">101</a>     }
<a name="102" href="#102">102</a> 
<a name="103" href="#103">103</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">int</strong> getOffset(<strong class="jxr_keyword">long</strong> instant) {
<a name="104" href="#104">104</a>         <strong class="jxr_keyword">return</strong> getInfo(instant).getOffset(instant);
<a name="105" href="#105">105</a>     }
<a name="106" href="#106">106</a> 
<a name="107" href="#107">107</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">int</strong> getStandardOffset(<strong class="jxr_keyword">long</strong> instant) {
<a name="108" href="#108">108</a>         <strong class="jxr_keyword">return</strong> getInfo(instant).getStandardOffset(instant);
<a name="109" href="#109">109</a>     }
<a name="110" href="#110">110</a> 
<a name="111" href="#111">111</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">boolean</strong> isFixed() {
<a name="112" href="#112">112</a>         <strong class="jxr_keyword">return</strong> iZone.isFixed();
<a name="113" href="#113">113</a>     }
<a name="114" href="#114">114</a> 
<a name="115" href="#115">115</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">long</strong> nextTransition(<strong class="jxr_keyword">long</strong> instant) {
<a name="116" href="#116">116</a>         <strong class="jxr_keyword">return</strong> iZone.nextTransition(instant);
<a name="117" href="#117">117</a>     }
<a name="118" href="#118">118</a> 
<a name="119" href="#119">119</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">long</strong> previousTransition(<strong class="jxr_keyword">long</strong> instant) {
<a name="120" href="#120">120</a>         <strong class="jxr_keyword">return</strong> iZone.previousTransition(instant);
<a name="121" href="#121">121</a>     }
<a name="122" href="#122">122</a> 
<a name="123" href="#123">123</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">int</strong> hashCode() {
<a name="124" href="#124">124</a>         <strong class="jxr_keyword">return</strong> iZone.hashCode();
<a name="125" href="#125">125</a>     }
<a name="126" href="#126">126</a> 
<a name="127" href="#127">127</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">boolean</strong> equals(Object obj) {
<a name="128" href="#128">128</a>         <strong class="jxr_keyword">if</strong> (<strong class="jxr_keyword">this</strong> == obj) {
<a name="129" href="#129">129</a>             <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">true</strong>;
<a name="130" href="#130">130</a>         }
<a name="131" href="#131">131</a>         <strong class="jxr_keyword">if</strong> (obj instanceof CachedDateTimeZone) {
<a name="132" href="#132">132</a>             <strong class="jxr_keyword">return</strong> iZone.equals(((CachedDateTimeZone)obj).iZone);
<a name="133" href="#133">133</a>         }
<a name="134" href="#134">134</a>         <strong class="jxr_keyword">return</strong> false;
<a name="135" href="#135">135</a>     }
<a name="136" href="#136">136</a> 
<a name="137" href="#137">137</a>     <em class="jxr_comment">// Although accessed by multiple threads, this method doesn't need to be</em>
<a name="138" href="#138">138</a>     <em class="jxr_comment">// synchronized.</em>
<a name="139" href="#139">139</a> 
<a name="140" href="#140">140</a>     <strong class="jxr_keyword">private</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a> getInfo(<strong class="jxr_keyword">long</strong> millis) {
<a name="141" href="#141">141</a>         <strong class="jxr_keyword">int</strong> period = (<strong class="jxr_keyword">int</strong>)(millis &gt;&gt; 32);
<a name="142" href="#142">142</a>         <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a>[] cache = iInfoCache;
<a name="143" href="#143">143</a>         <strong class="jxr_keyword">int</strong> index = period &amp; cInfoCacheMask;
<a name="144" href="#144">144</a>         <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a> info = cache[index];
<a name="145" href="#145">145</a>         <strong class="jxr_keyword">if</strong> (info == <strong class="jxr_keyword">null</strong> || (<strong class="jxr_keyword">int</strong>)((info.iPeriodStart &gt;&gt; 32)) != period) {
<a name="146" href="#146">146</a>             info = createInfo(millis);
<a name="147" href="#147">147</a>             cache[index] = info;
<a name="148" href="#148">148</a>         }
<a name="149" href="#149">149</a>         <strong class="jxr_keyword">return</strong> info;
<a name="150" href="#150">150</a>     }
<a name="151" href="#151">151</a> 
<a name="152" href="#152">152</a>     <strong class="jxr_keyword">private</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a> createInfo(<strong class="jxr_keyword">long</strong> millis) {
<a name="153" href="#153">153</a>         <strong class="jxr_keyword">long</strong> periodStart = millis &amp; (0xffffffffL &lt;&lt; 32);
<a name="154" href="#154">154</a>         <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a> info = <strong class="jxr_keyword">new</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a>(iZone, periodStart);
<a name="155" href="#155">155</a>         
<a name="156" href="#156">156</a>         <strong class="jxr_keyword">long</strong> end = periodStart | 0xffffffffL;
<a name="157" href="#157">157</a>         <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a> chain = info;
<a name="158" href="#158">158</a>         <strong class="jxr_keyword">while</strong> (<strong class="jxr_keyword">true</strong>) {
<a name="159" href="#159">159</a>             <strong class="jxr_keyword">long</strong> next = iZone.nextTransition(periodStart);
<a name="160" href="#160">160</a>             <strong class="jxr_keyword">if</strong> (next == periodStart || next &gt; end) {
<a name="161" href="#161">161</a>                 <strong class="jxr_keyword">break</strong>;
<a name="162" href="#162">162</a>             }
<a name="163" href="#163">163</a>             periodStart = next;
<a name="164" href="#164">164</a>             chain = (chain.iNextInfo = <strong class="jxr_keyword">new</strong> Info(iZone, periodStart));
<a name="165" href="#165">165</a>         }
<a name="166" href="#166">166</a> 
<a name="167" href="#167">167</a>         <strong class="jxr_keyword">return</strong> info;
<a name="168" href="#168">168</a>     }
<a name="169" href="#169">169</a> 
<a name="170" href="#170">170</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">class</strong> <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a> {
<a name="171" href="#171">171</a>         <em class="jxr_comment">// For first Info in chain, iPeriodStart's lower 32 bits are clear.</em>
<a name="172" href="#172">172</a>         <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">long</strong> iPeriodStart;
<a name="173" href="#173">173</a>         <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <a href="../../../../org/goda/time/DateTimeZone.html">DateTimeZone</a> iZoneRef;
<a name="174" href="#174">174</a> 
<a name="175" href="#175">175</a>         <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a> iNextInfo;
<a name="176" href="#176">176</a> 
<a name="177" href="#177">177</a>         <strong class="jxr_keyword">private</strong> String iNameKey;
<a name="178" href="#178">178</a>         <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">int</strong> iOffset = Integer.MIN_VALUE;
<a name="179" href="#179">179</a>         <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">int</strong> iStandardOffset = Integer.MIN_VALUE;
<a name="180" href="#180">180</a> 
<a name="181" href="#181">181</a>         <a href="../../../../org/goda/time/tz/CachedDateTimeZone.html">Info</a>(<a href="../../../../org/goda/time/DateTimeZone.html">DateTimeZone</a> zone, <strong class="jxr_keyword">long</strong> periodStart) {
<a name="182" href="#182">182</a>             iPeriodStart = periodStart;
<a name="183" href="#183">183</a>             iZoneRef = zone;
<a name="184" href="#184">184</a>         }
<a name="185" href="#185">185</a> 
<a name="186" href="#186">186</a>         <strong class="jxr_keyword">public</strong> String getNameKey(<strong class="jxr_keyword">long</strong> millis) {
<a name="187" href="#187">187</a>             <strong class="jxr_keyword">if</strong> (iNextInfo == <strong class="jxr_keyword">null</strong> || millis &lt; iNextInfo.iPeriodStart) {
<a name="188" href="#188">188</a>                 <strong class="jxr_keyword">if</strong> (iNameKey == <strong class="jxr_keyword">null</strong>) {
<a name="189" href="#189">189</a>                     iNameKey = iZoneRef.getNameKey(iPeriodStart);
<a name="190" href="#190">190</a>                 }
<a name="191" href="#191">191</a>                 <strong class="jxr_keyword">return</strong> iNameKey;
<a name="192" href="#192">192</a>             }
<a name="193" href="#193">193</a>             <strong class="jxr_keyword">return</strong> iNextInfo.getNameKey(millis);
<a name="194" href="#194">194</a>         }
<a name="195" href="#195">195</a> 
<a name="196" href="#196">196</a>         <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">int</strong> getOffset(<strong class="jxr_keyword">long</strong> millis) {
<a name="197" href="#197">197</a>             <strong class="jxr_keyword">if</strong> (iNextInfo == <strong class="jxr_keyword">null</strong> || millis &lt; iNextInfo.iPeriodStart) {
<a name="198" href="#198">198</a>                 <strong class="jxr_keyword">if</strong> (iOffset == Integer.MIN_VALUE) {
<a name="199" href="#199">199</a>                     iOffset = iZoneRef.getOffset(iPeriodStart);
<a name="200" href="#200">200</a>                 }
<a name="201" href="#201">201</a>                 <strong class="jxr_keyword">return</strong> iOffset;
<a name="202" href="#202">202</a>             }
<a name="203" href="#203">203</a>             <strong class="jxr_keyword">return</strong> iNextInfo.getOffset(millis);
<a name="204" href="#204">204</a>         }
<a name="205" href="#205">205</a> 
<a name="206" href="#206">206</a>         <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">int</strong> getStandardOffset(<strong class="jxr_keyword">long</strong> millis) {
<a name="207" href="#207">207</a>             <strong class="jxr_keyword">if</strong> (iNextInfo == <strong class="jxr_keyword">null</strong> || millis &lt; iNextInfo.iPeriodStart) {
<a name="208" href="#208">208</a>                 <strong class="jxr_keyword">if</strong> (iStandardOffset == Integer.MIN_VALUE) {
<a name="209" href="#209">209</a>                     iStandardOffset = iZoneRef.getStandardOffset(iPeriodStart);
<a name="210" href="#210">210</a>                 }
<a name="211" href="#211">211</a>                 <strong class="jxr_keyword">return</strong> iStandardOffset;
<a name="212" href="#212">212</a>             }
<a name="213" href="#213">213</a>             <strong class="jxr_keyword">return</strong> iNextInfo.getStandardOffset(millis);
<a name="214" href="#214">214</a>         }
<a name="215" href="#215">215</a>     }
<a name="216" href="#216">216</a> }
</pre>
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